Pacific Plankton Sampling To Give Glimpse Into Food Web

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The longest sampling trawl of tiny ocean creatures called
plankton is under way across the Pacific, where little is known
about these critters that make up the base of the ocean's food
web.

Scientists onboard the NOAA ship Okeanos Explorer will
have covered a total of more than 5,100 miles (8,207 kilometers)
across a portion of the
Pacific Ocean by the time the two-part project is complete.
The study comes as
plankton across the globe have been disappearing over the
past century at a rate of about 1 percent per year, according to
a recent study.

Plankton's many forms

Plankton consists of drifting microscopic plants
(phytoplankton), animals (zooplankton),
bacteria (bacterioplankton) and viruses
(virioplankton) that inhabit oceans, seas and bodies of
fresh water. They are the most abundant form of life in the
ocean. In fact, all other marine life is dependent upon plankton
for food.

Phytoplankton are the world's top source of oxygen and are
responsible for 90 percent of all the photosynthesis — the
conversion of energy from sunlight into organic compounds — that
takes place on Earth.

"This project will provide valuable information on plankton for
an area of the world that has been largely unsampled," said Lora
Clarke, a National Oceanic and Atmospheric Administration (NOAA)
Fisheries Service scientist onboard the Okeanos Explorer
who oversaw the first leg of the plankton tow. "We will obtain
the necessary baseline data to allow an examination of the
relative richness and variety of plankton and how this might
influence fish, turtle and mammal species. Understanding patterns
of plankton biodiversity will help scientists to understand
factors influencing global productivity."

Sailing from Guam en route to Hawaii in late August, the research
team conducted the first leg of the plankton sampling by towing a
device that filters plankton from the water onto rolling silk
screens that can later be analyzed in the lab. The ship trawled
for 14 days across more than 3,100 miles (4,988 km). After a
layover in Hawaii, the ship departed Oct. 19 for San Francisco,
with NOAA's Stephanie Oakes leading the next phase of the
sampling mission.

For the second leg of the sampling mission, researchers are
studying plastic marine debris as they cross the so-called
Great Pacific Garbage Patch, a large area in the North
Pacific Ocean known for accumulations of plastic marine debris.

Plankton and plastic

The ship will cross the breadth of the area and take one of the
first measurements of its width by carefully analyzing plastic
particles caught in the ship's nets.

Plastic debris has many observable effects on marine life.
Thousands of marine animals die each year from interactions with
plastic litter, including plastic fishing line and gear. What is
less known is how plastics affect the smallest organisms on which
other marine life feed.

"The information on the biodiversity of plankton across the
Pacific will be exciting to see," said Michael Ford of NOAA, who
is leading the project. "The size spectrum of plastic particles
and the size of the Garbage Patch is just as exciting. By putting
the two data series together, we can begin to make connections
between plankton and plastic and possibly determine how much of
an impact the plastic debris is having on this part of the marine
food chain — it's an incredible opportunity."